Filter

ABSTRACT

The present invention discloses a filter comprising a tube extending from a first end to a second end and having a bore with an internal cross-sectional area. The tube comprises an inlet with an inlet cross-sectional area which is positioned through the first end of the tube. The tube also comprises an outlet with an outlet cross-sectional area, wherein the inlet cross-sectional area is less than the outlet cross-sectional area and so debris small enough to enter the inlet will tend not to block the outlet, which is larger. The filter further comprises a plurality of further inlets, often slots, in the tube between an outside thereof and the bore. In a preferred embodiment, the first end may be tapered and especially dome shaped. This helps to direct debris towards an outside of the tube, where it is less likely to be drawn into the filter and potentially block it or a downstream component, such as a nozzle. The filter may be attached to a pipeline and a nozzle.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/301,536, filed on Oct. 3, 2016 and titled “Filter,” which was anational stage application of Patent Cooperation Treaty ApplicationSerial No. PCT/GB2015/051056, filed Apr. 7, 2015, titled “Filter,” whichclaimed priority under 35 U.S.C. § 119 to United Kingdom PatentApplication Serial No. 1406174.1, filed on Apr. 4, 2014, and to UnitedKingdom Patent Application Serial No. 1407584.0, filed Apr. 30, 2014,the disclosure of each of the foregoing applications is herebyincorporated by reference.

INTRODUCTION TO THE INVENTION

This invention relates to a filter particularly but not exclusively aspart of, or for a nozzle connected to a pipeline.

Fluid flow systems, such as sprinkler systems are widely used in onshoreand offshore installations, such as oil and gas platforms, to contain orsuppress fire. During operation of the sprinkler system, it is likelythat scale, debris and other pollutants will build up and become aproblem. Scale is typically formed by the precipitation of mineralcompounds from water, such as calcium carbonate or calcium sulphate, dueto pressure and/or temperature changes in the pipeline. Corrosion inpipelines can build up along the inner wall of pipe and also results indebris entering the system. Marine growth can also cause blockageproblems. Salts can also crystallise and cause blockage problems.

It is a regular occurrence for nozzles of sprinkler systems to block dueto this build-up, and this can cause the whole system to becomeredundant. If such nozzles become blocked, the ability of the sprinklersystem to contain or suppress a fire could be severely impeded. Thiscould hinder the safe escape of platform personnel.

Other fluid flow systems such as burner heads can also suffer from avariety of debris which inhibits flow.

Debris can pose a problem if it is distributed outwith the sprinklersystem. Fluid is typically ejected from the exit point at highvelocities and any debris present can cause injury to personnel. It hasbeen known to cut faces and has the potential to cause serious eyeinjuries.

Traditional means to tackle the presence of scale, or other debris whichcan potentially block the nozzle or cause injuries, include an upstreamscreen which blocks larger particles. However this is stillunsatisfactory partly because the screens themselves become blocked andinhibit or prevent fluid coming through the exit point of the fluidsystem, such as a sprinkler.

WO2014/009713 describes a nozzle apparatus with an entry segregator 22having an axial passage 12. Slots 25 in the entry segregator 22 provideadditional filtration capacity to other components described therein.

WO2014/009714 describes a nozzle system comprising a nozzle apparatus influid communication with a pipeline. The nozzle apparatus comprises afirst and second inlet and an outlet. The nozzle apparatus extends intothe pipeline such that a portion of the first inlet is in the centre ofthe pipeline. This can reduce the likelihood of the nozzle apparatusbecoming blocked due to the build-up of debris on the inner edge of thepipeline.

Whilst generally satisfactory, the inventor of the present invention hasdeveloped an improved filter. Thus, an object of the present inventionis to further mitigate the problem of blockages.

According to a first aspect of the present invention, there is provideda filter comprising:

-   -   a tube extending from a first end to a second end, the tube        having a bore with an internal cross-sectional area;    -   an inlet to the tube, the inlet being positioned through the        first end of the tube and the inlet having an inlet        cross-sectional area;    -   an outlet from the tube the outlet having an outlet        cross-sectional area;    -   a plurality of further inlets in the tube between an outside        thereof and the bore;    -   wherein the inlet cross-sectional area is less than the outlet        cross-sectional area.

The first end may be tapered and especially dome shaped. That is, thecentre of the first end (often perimeter of the end inlet) may extendlongitudinally further than an outer portion of the first end. In thisway, debris is in use directed towards an outside of the tube, where itis less likely to be drawn into the filter and potentially block it or adownstream component, such as a nozzle.

The further inlets may be slots. The further inlets may extend generallyparallel (+/−10 degrees) to the (normally longitudinal) direction fromthe first to the second end.

The number of further inlets depends on the diameter of the filter.There is normally at least 8 further inlets, and for a 0.5″ diameterfilter, there are normally up to 20 further inlets.

For embodiments especially according to the first aspect of theinvention, the further inlets normally have a width of 1-3 mm or 1.5-2.5mm. The spacing between the further inlets is normally between 50% and150% larger than the width of the further inlets. For example thefurther inlets may be 1 mm width, and spaced apart by 2 mm.

The length of the further inlets can vary depending on the applicationof the filter e.g. the size of a pipe to which it may be attached but isnormally at least 1.5 cm, optionally at least 2 cm, or normally forlarger pipes, more than 3 cm. They may extend up to 10 cm or up to 8 cm,although this largely depends on the size of the pipe to which they areattached.

Alternatively, the further inlets may extend for more than 4 cm andoptionally up to 6 cm.

The further inlets may extend for up to 75% or up to 50% of the lengthof the tube. The further inlets may extend for a portion of the tubebetween the first end and the middle of the tube.

The tube may be circular in cross-section. Preferably the tube extendslongitudinally. The outlet may be at the second end.

The internal cross-sectional area of the tube is normally taken at thenarrowest internal point in the tube. However, preferably the internalcross-section of the tube is the same along the majority if not all ofits length, such as at least 75%, or at least 90 or 95% of its length.

Said internal cross-sectional area of the tube normally has a height towidth ratio of at most 2:1, normally 1.5:1, 1.1:1 or equal i.e. 1:1. Itis normally circular.

The inlet cross-sectional area may be at least 75%, preferably at least90% and ideally 100%, of the internal cross-sectional area. This assistsin maintaining pressure and flow rate in the filter in use.

The tube may be 2-4 inches long.

The filter is normally for a pipeline. The filter normally has amounting means for mounting to the pipeline in use. This may be a clip,threaded body (especially outer body), a snap-fit connection or othersuitable device. A threaded outer body is preferred. This may beprovided around the tube, with a wider outer diameter compared to thetube. It is normally provided adjacent the end.

The tube, especially at the outlet end, normally comprises a secondmounting means, normally on the inside, for mounting a nozzle thereto.For example a threaded bore.

Whilst the filter described herein may be suitable for a variety ofapplications which require clear flow of fluid, it is preferred for usein pipelines, especially as a nozzle for a pipeline. For example, aburner head for flaring oil or gas, water delivery lines, especially asprinkler system for firefighting or fire containment.

According to a second aspect of the invention, there is provided apipeline comprising a pipe, and the filter as described herein.

Thus the filter extends into the pipeline. In use, it can filter debrisfrom entering which can mitigate the blockages or reduce the number ofblockages, experienced downstream, such as in a nozzle.

A reducing bush may be used to size the filter into a suitable socket inthe pipeline. A wider diameter coupling (compared to the pipe) may alsobe provided between an end of the pipe and the outer body or reducingbush.

Preferably the length of the tube, is longer, and this extends beyondany reducing bush.

This is especially useful for filters installed at elbow and/orT-joints.

Alternatively, a weld-o-let fitting may be used.

The portion of the tube adjacent the reducing bush, or weld-o-let, ispreferably substantially solid—the slots extending in a portion of thetube outwith this area. This can improve the mechanical mounting. Forexample, at least 75% of this area may be free from slots or at least95%.

The filter may be added to an end of the pipeline, and extend therein,substantially parallel (+/−10 degrees) to the main longitudinal axis ofthe pipeline. Alternatively, it may be provided at an angle such assubstantially at a right angle (+/−10 degrees) to the main longitudinalaxis of the pipeline. In the latter case, the first end (including theend inlet where provided) extends into the central 10% of the pipeline,that is +/−10% of the inner diameter of the pipeline around the centralaxis. Optionally +/−5%. The end may not be in the exact centre. It hasbeen found especially useful to be 3-4% or 3-5% off-centre, that isspaced by such a proportion away from the main longitudinal axis basedon the internal diameter of the pipeline. For elbow joins it ispreferred to be slightly above the central axis, for other joins,slightly below.

The filter described herein may be provided as a single piece and in usealso functions as an adaptor to attach a nozzle to a pipeline or indeedfor other purposes, such as at a join between two pipes For examplebetween a larger (e.g. 2″) pipe to smaller (e.g. 0.5″) pipe to protectthe pipe bore.

The outlet described herein is normally the outlet of the tube, beforeany nozzle portion, or attached nozzle.

However, where a nozzle is included, or attached, preferably thecross-sectional area of the end inlet is +/−20% of the totalcross-sectional area of the outlet of the nozzle, normally +/−10% or+/−5%. But preferably the end inlet is no larger than the nozzle outlet.In this way, any debris which is small enough to proceed through the endinlet, will not be large enough to block the nozzle outlet.

Thus an advantage of such embodiments is that they may be used with avariety or new or conventional nozzles. Alternatively, it may beprovided together with a nozzle, either formed as one piece or otherwiseconnected and sold to the end user as a single item.

The pipe may have an inner diameter from 0.5″ optionally more than 0.75″or more than 1″. Certain embodiments may be up to 3.5″, up to 3″ or upto 2″.

Thus, according to a third aspect of the invention, there is provide anozzle apparatus, comprising a nozzle and the filter described herein.

Preferably the bore of the nozzle, especially the outlet of the nozzle,is not reduced by the combination of the filter and the nozzle.Accordingly, the filter may be sized such that the bore of the nozzle,especially the outlet of the nozzle, is not reduced in size whencombined with the filter.

According to a fourth aspect of the present invention, there is provideda nozzle apparatus, comprising:

-   -   a filter comprising a tube extending from a first end to a        second end, the tube having a bore with an internal        cross-sectional area;    -   an inlet to the tube, the inlet being positioned through the        first end of the tube and the inlet having a first inlet        cross-sectional area;    -   an outlet from the tube the outlet having an outlet        cross-sectional area;    -   a plurality of further inlets in the tube between an outside        thereof and the bore;    -   a nozzle with a nozzle outlet, the nozzle outlet having a nozzle        outlet cross-sectional area    -   wherein the inlet cross-sectional area of the filter is smaller        than the outlet cross-sectional area of the nozzle.

According to a fifth aspect of the present invention, there is provideda filter comprising:

-   -   a tube extending from a first end to a second end, the tube        having a bore with an internal cross-sectional area;    -   a side inlet to the tube, the side inlet having a side inlet        cross-sectional area;    -   an outlet from the tube;    -   a plurality of further inlets in the tube between an outside        thereof and the bore;    -   wherein the side inlet cross-sectional area is at least 75% of        the internal cross-sectional area;    -   and wherein the side inlet is provided through a side face of        the tube, between the first and second ends.

Thus filters in accordance with the fifth aspect of the presentinvention require a side inlet whereas earlier aspects of the inventiondo not. Accordingly, there are distinct embodiments of theinvention—those with a side inlet as described herein, and thosewithout.

The pipeline of the second aspect of the invention and nozzle apparatusaccording to the third and/or fourth aspect of the inventions, caninclude a filter according to the fifth aspect of the inventionoptionally in place of the filter according to the first aspect of theinvention.

Thus advantages can be derived from filters in accordance with the fifthaspect of the present invention. First, the inlet cross-sectional areais at least 75%, preferably at least 90% and ideally 100%, of theinternal cross-sectional area. This assists in maintaining pressure andflow rate in the filter in use.

Second, given the side inlet is on a side face of the tube, debris inthe pipeline in use, is less likely to enter the filter and block it.

The tube has a main longitudinal axis (parallel to the main direction offluid flow in use); and the side inlet is provided in an inlet plane;the inlet plane is normally at an angle of −20 degrees to +20 degrees tothe main longitudinal axis of the tube. Preferably it is −10 degrees to+10 degrees or ideally essentially parallel.

The outlet of the tube may have an outlet plane, and the inlet plane maybe at an angle of 70-110 degrees relative to the outlet plane.Optionally 80-100 degrees and ideally around 90 degrees, relative to theoutlet plane.

Where the side inlet is thus provided along its circular outer face, theinlet plane is one extending through three points on the perimeter ofthe at least one inlet. The end inlet and outlet may be defined in thesame manner if required.

The at least one side inlet may be provided closer to the first end thanthe second (normally outlet) end.

The cross-sectional area of the side inlet normally has a height towidth ratio of at most 2:1, normally 1.5:1, 1.1:1 or equal i.e. 1:1. Itis normally circular.

Preferably the diameter of the side inlet is least 75% of the diameterof the internal cross-section, preferably at least 90% and ideally 100%.

As for the first aspect of the invention, the tube may comprise asecond, normally end, inlet having a cross-sectional diameter smallerthan the side inlet. The end inlet may be through the first end (ratherthan through a side face) of the tube. Normally the end inlet has across-sectional area smaller than an outlet cross-sectional area.

The cross-sectional area of the tube is normally the same shape as theside inlet.

Especially for embodiments in accordance with the fifth aspect of theinvention there is normally at least 8 further inlets, optionally atleast 20 or more than 30 further inlets. The further inlets normallyhave a width of 1-4 mm or 1-2 mm. The spacing between the further inletsis normally the same (+/−up to 20%) as the width of the further inlets.For example the further inlets may be 1 mm width, and spaced apart by 1mm.

Required and optional features of the filter in accordance with theearlier, especially the first aspect, of the present invention which arenot part of the fifth aspect of the invention, are considered asoptional features for the filter in accordance with the fifth aspect ofthe invention.

In particular, the first end may be tapered, especially dome shaped.That is, the centre of the first end (often perimeter of the end inlet)may extend longitudinally further than an outer portion of the firstend.

An indicator may be provided, such as at the second end, which allows auser to know the position of the at least one side inlet, which may beconcealed by the surrounding pipeline.

Thus debris which is large enough to enter the at least one side inlet,tends not to enter the filter because the largest inlet (the sideinlet), can be faced away from the main flow direction of the fluid.

According to a sixth aspect of the invention there is provided a methodof installing a filter as described herein, into a pipeline, such thatthe at least one side inlet does not face the flow of fluid through thepipeline.

Preferably it is orientated at 80-100 degrees to the flow of fluid inthe pipeline. Alternatively, it may be opposite the flow of fluid in thepipeline. Said flow of fluid is the main direction of the fluid flow inthe pipeline.

According to a seventh aspect of the present invention, there isprovided a filter comprising:

-   -   a tube extending from a first end to a second end; the tube        having a bore with an internal cross-sectional area and a main        longitudinal axis;    -   a side inlet to the tube, the side inlet having a side inlet        cross-sectional area and provided in an inlet plane;    -   an outlet from the tube, the outlet having an outlet        cross-sectional area and provided in an outlet plane;    -   a plurality of further inlets in the tube between an outside        thereof and the bore;    -   wherein the side inlet cross-sectional area is at least 75% of        the internal cross-sectional area;    -   and wherein the inlet plane is at an angle of −20 degrees to +20        degrees to the main longitudinal axis of the tube.

The filter according to the seventh aspect of the invention mayindependently comprise the features described herein with respect to thefilter according to the fifth aspect of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample only, with reference to the accompanying figures, in which:

FIG. 1 shows a side view of a filter arrangement in accordance with oneaspect of the present invention;

FIG. 2 shows a three-dimensional view of a filter arrangement;

FIG. 3 shows a filter arranged in a pipeline connected with a tubularconnector;

FIG. 4 shows a filter arranged in a pipeline connected with an elbowconnector;

FIG. 5 shows a filter arranged in a pipeline connected with a T-junctionconnector;

FIG. 6a is a cross-section perspective view of a filter with an inletlocated in the side wall in accordance with another aspect of thepresent invention;

FIG. 6b is a perspective view of the FIG. 6a filter spaced between apipe shown in cross-section, and a nozzle in a first arrangement;

FIG. 7a is a front perspective view of the FIG. 6a filter spaced betweena pipe, shown in cross-section, and a nozzle in a second arrangement;

FIG. 7b is a front view of the FIG. 7a filter and pipe in the secondarrangement;

FIG. 8 is a perspective view of the FIG. 6a filter spaced between anelbow connector connected to a pipe, shown in cross-section, and anozzle in a third arrangement; and

FIG. 9 is a perspective view of the FIG. 6a filter spaced in between aweld let adaptor in a pipe, shown in cross-section and a nozzle in afourth arrangement.

DETAILED DESCRIPTION

FIGS. 1 and 2 show a side and three-dimensional view of a distinctembodiment of a filter 10 in accordance with one aspect of the presentinvention.

The filter 10 is formed from a tube 12 extending from a first end to asecond end. An inlet 18 is positioned through the first end of the tubeand the inlet has a cross-sectional area less than the cross-sectionalarea of the outlet 16 of the tube 12 and normally less than the outletof an associated nozzle in use.

The inlet 18 also has a cross-sectional area less than thecross-sectional area of the internal bore of the tube 12.

Slots 20 extend longitudinally along the first part of the side wall 13of the tube 12 from the first end of the tube to a threaded bush 22. Theslots are 1 mm and above in width and, in this example, are of asuitable length where two of the slots equals the flow required to givethe corresponding K-Factor of the associated nozzle. For suchembodiments, the volume of water that will pass through two slots willbe greater or equal to the flow required by the nozzle. The K-factor isdefined as the flow rate of a nozzle given by q=K√{square root over(p)}, where q is the flow rate in litres per minute, p is the pressureat the nozzle (or filter) in Bar and K is the K-factor. Consequently, ifthe inlet 18 becomes blocked, then the slots will allow the correctoperating volume of fluid through to the nozzle. The volume required insuch embodiments is three times the volume required to feed the nozzleat all times. Therefore, the inlet 18 plus four slots 20 can equal threetimes the dispersion flow rate of the nozzle. For high viscosity fluids,the slots 20 will be larger in order to reduce blocking. For example,where the fluid is water, the slot width is 1 mm, whereas for foam theslot 20 width is 1.5 mm or greater. The number of slots 20 may be, forexample, 4 to 24 or greater depending on the dimensions of the filter10. In other embodiments, the slots need not provide the flow ratedescribed above for this embodiment.

The filter 10 is adapted to connect to a standard nozzle (not shown)typically used for fire sprinkler systems. Once the filter 10 isconnected to a nozzle, the inlet 18 has a cross-sectional area less thanthe cross-sectional area of the outlet of the nozzle.

A bush thread is provided to connect the filter to a nozzle. In thisportion of the filter, the filtering mechanism is dormant, but thisportion provides structural support and enables for faster production asthis portion requires less machining to manufacture.

The inner chamber of the filter 10 is sized such that the diameter (orother dimension) is matched to the inlet of the nozzle. This allows fullflow into the nozzle without restriction to the flow in the innerchamber of the filter 10. This region will be free flowing withoutdebris that would normally block the nozzle's exit orifice.

The benefits of this embodiment are that it can work in any position ofpipe from Elbow/Tee/Down Pipe and Up Pipe with it being positioned outwith the concentric flow path, the first inlet should be within the IDof the main flow path with the slots being positioned in a debrisentrapment area in the pipe line (Elbow Cavity—Tee Cavity—Weld LetCavity) out with concentric flow path.

This will mean that there will be a reduced risk of operatorinstallation error as NPT threads do not always match up with each otherand this can manipulate the positioning of the filters to the concentricflow path. The strength of this filter is also improved as the slots arenot the full body length of the internal section of the adaptor, in thisembodiment, but are based specifically on two slots to allow the correctflow through to the nozzle, this also enables manufacture time to bereduced without compromise to flow.

Each size of filter is given a K-Factor of its own to ensure that theK-Factor of the nozzle is always achieved when choosing the correctvariation for any nozzle with any fluid.

In one example, the inlet 18 has a diameter of approximately 3.9 mmcompared with a nozzle outlet diameter of approximately 4 mm and afilter outlet of 14 mm. In an alternative embodiment, if the nozzle hasan exit diameter of 10 mm the inlet 18 diameter to the filter is 9.9 mmor less. The inlet 18 and the slots 20, in this embodiment, are sizedsuch that the flow rate through the filter 10 is equal to the flow ratethrough a tube having an open bore of similar size. Consequently,without wishing to be bound by theory, the flow of fluid through thenozzle is equivalent to the full bore flow rate of an equally sized tubeopen ended tube.

The first end of the filter 10 is a debris deflector formed in a taperedor dome-shaped end 19 such that the centre of the first end extendslongitudinally further than an outer portion of the first end. The shapeof the first end of the tube 12 encourages debris flowing through thepipeline to proceed in a flow direction away from the inlet 18.

The curvature of the debris deflector 19 limits the availability of flatareas of impact (i.e. surfaces at substantially 90 degrees to thedirection of flow) for flowing debris and encourages debris in the flowto flow beyond the inlet 18. The rounded end section of the filterlimits the point of fixture for debris close to the inlet, and anydebris flowing in the pipeline is forced around the filter and down pastthe filter into the debris entrapment area 28 within the pipe (shown inFIGS. 3, 4 and 5). The smooth edge/surface of the debris deflectorreduces friction of the filter which propels debris away from the inlet.The cylindrical shape and/or curved surfaces also provide a smootherflow path of water or delivery fluid for example oil or firefightingfoam. The cylindrical and/or curved surfaces further reduce the areaswhere salt crystallisation can begin allowing a free flow area.

FIG. 3 shows the filter 10 arranged in a pipeline 40. The filter 10 isconnected to a pipe 30, a tubular coupling 32 and a reducing bush 26.Debris 60 flows around the dome-shaped end 19 of the filter 10 and intothe tubular coupling 32.

The portion of the tube 12 adjacent to the reducing bush 26 issubstantially solid. The slots 20 extend in a portion of the tube 12substantially outwith the reducing bush 26. In this example, 95% of theportion of the tube 12 adjacent to the reducing bush 26 is free fromslots 20.

The slots 20 are located substantially within the debris entrapment area28. In use, the debris flows in the pipeline 30, around and down pastthe filter 10 into the debris entrapment area 28.

FIG. 4 shows the filter 10 arranged in a pipeline 40, connected to thepipeline via an elbow connector 44.

FIG. 5 shows the filter 10 arranged in a pipeline 40, connected to thepipeline via a T-junction connector 42.

With the above-described arrangement small debris that enters the inlet18 is able to pass freely through the filter 10 and into and out of thenozzle. Because the inlet 18 has a smaller cross-sectional area to theoutlet of the nozzle, the risk of blockages in the nozzle caused byflowing debris is significantly reduced.

Additionally, the combination of the inlet 18 and the slots 20 providesthe filter 10 with a K-factor equivalent or greater than the K-factor ofan open tube of the same dimensions as the tube 12 of the filter 10. Thefilter 10 filters debris from the flow while maintain full bore flow tothe nozzle.

Improvements and modifications may be made, without departing from thescope of the invention.

Various modifications to the detailed designs as described above arepossible.

For example, FIG. 6a shows a distinct embodiment of a filter 110comprising a tube 112 having a bore (not shown) extending therethrough,a side inlet 114 in a side wall 113, an end inlet 118, and an outlet116. Slots 120 extend longitudinally along the first part of the sidewall 113 of the tube 112 from the end inlet to a threaded bush 122.

The threaded bush 122 is a mounting means provided over the tube 112 atthe outlet 116 end, and is used to secure in a pipeline or a reducingbush as described further below. An inner thread (not shown) is alsoprovided at the outlet end, for connection to a nozzle.

The end inlet 118 is provided on a dome 119, which extends from the tube114. The end inlet 118 has a smaller diameter (and thereforecross-sectional area) than the outlet 116. In contrast, the diameter ofthe side inlet 114 is the same as that as the bore of the tube 114, andthe outlet 116.

Moreover, the outlet 116 has a plane which is through the cross-sectionof the tube 112, at right angles to the main longitudinal axis thereof.Whilst the side inlet 114 is in a side of the tube 112, and has a planewhich is generally at right angles to the plane of the outlet 116.

The end inlet 118 has a cross-sectional area the same full bore as anozzle 150 (shown in FIG. 6b ) to be greater than the nozzle's k-factor.

The benefits of such features will become apparent in the followingdescription on in use arrangements.

FIG. 6b illustrates the filter 110 in a pipe 130 via a tubular coupling132 and reducing bush 134. A nozzle 150 is received into the bore of thetube 112 at the outlet 116 via the internal thread. In use, fluid flowsthrough the pipe 130 in the direction of arrow 136. Large pieces ofdebris, liable to block the nozzle 150 are inhibited to flow through themost direct inlet (the end inlet 118) because of its reduced size.Debris that can and does flow therethrough tends to be small enough tobe less likely to cause blockages in the nozzle 110. But in any case,the dome shape or bevelled edge 119 of the end of the tube 112 alsoencourages the debris to go past the end inlet 118 and combined with theflow pressure, gather outside of the filter 110, rather than enter theside inlet 114

Fluid flow and pressure, is nonetheless maintained through the sideinlet 114, and the slots 120. Thus the embodiment provides the benefitof full bore pressure applied to the nozzle because the inlet 114 is notrestrictive in size, but also a reduced likelihood of blockages, becauseit is orientated at right angles to the outlet 116, i.e. on the side ofthe tube 112 where debris is likely to pass by, partly driven by in usefluid pressure.

In FIGS. 7a and 7b , the filter 110 is provided in a T-piece connector142 of a pipeline 140. A nozzle 150 is provided within the filter 110 aspreviously described. The larger (side) inlet 114 is orientated awayfrom the fluid flow through the pipeline, represented by arrow 146. Inthis way, debris in the fluid is less likely to proceed through thelargest inlet (the side inlet 114), and cause blockage problemsdownstream. In FIG. 7a the inlet 114 is orientated at 90 degrees to thefluid flow 146, in FIG. 7b it is orientated at 180 degrees i.e. oppositethe fluid flow. Nevertheless the full bore access of the side inlet 114maintains flow rate and pressure to the nozzle 150.

The filter 110 is positioned within the T-piece connector 142 such thatthe end of the tube 112 is slightly below the concentric flowpath of thepipeline 140, or alternatively, just below the longitudinal axis of thepipeline 140. In this manner, the entrapment area for debris flowing inthe pipeline is maximised in the T-piece connector 142 arrangement ofthe pipeline 140 in the region between the slots 120 and the pipeline140.

An indicator arrow 148 is provided on the outer face of the bush 122which corresponds with the orientation of the side inlet 114.Accordingly a user fitting the nozzle 150 and filter 110, will know therotational position of the side inlet 114 from the indicator arrow 148,and can position relative to the flow direction.

FIG. 8 illustrates the filter 110 is provided in an elbow adapter 242 ofa pipeline 240. The nozzle 150 is provided within the filter 110 aspreviously described. The larger (side) inlet 114 is orientated atninety degrees to the fluid flow through the pipeline, represented byarrow 246. A smaller end inlet 118 is provided at an end of the tube112. Debris in the fluid is less likely to proceed through the largestinlet (the side inlet 114), and cause blockage problems downstreambecause the debris flows between the slots 120 and the inner face of theelbow adaptor 242. Even when debris is present in this region, the sideinlet 114 maintains flow rate and pressure to the nozzle 150.

Furthermore, deposits such as scale and marine growth build upconcentrically within the pipeline, and may inhibit flow along thepipeline. The deposits may eventually break off and flow within thepipeline towards the filter 110. Typically, any debris flow toward theslots and the debris is less likely to flow through the side inlet 114.

The filter is positioned within the elbow connector such that the end ofthe tube 112 is slightly above the centre of the pipeline, oralternatively, positioned just above the longitudinal axis of the pipe.

In FIG. 9, the filter 110 is provided in a weld let adaptor 342 of apipeline. A nozzle 150 is provided within the filter 110 as previouslydescribed, and its second inlet 118 slightly below the central axis ofthe pipe 342.

Depending on the dimensions of the pipeline, and the nozzle, a varietyof couplings, and reducing bushes may or may not be used, as required,to fit the nozzle to the pipeline. Certain embodiments use the filterwithout a nozzle such as between individual pipe joins in a pipeline.

Following from the above description, it should be apparent to those ofordinary skill in the art that, while the methods and apparatuses hereindescribed constitute exemplary embodiments of the present invention, theinvention described herein is not limited to any precise embodiment andthat changes may be made to such embodiments without departing from thescope of the invention as defined by the claims. Additionally, it is tobe understood that the invention is defined by the claims and it is notintended that any limitations or elements describing the exemplaryembodiments set forth herein are to be incorporated into theinterpretation of any claim element unless such limitation or element isexplicitly stated. Likewise, it is to be understood that it is notnecessary to meet any or all of the identified advantages or objects ofthe invention disclosed herein in order to fall within the scope of anyclaims, since the invention is defined by the claims and since inherentand/or unforeseen advantages of the present invention may exist eventhough they may not have been explicitly discussed herein.

What is claimed is:
 1. A filter comprising: a tube extending from afirst end to a second end, the tube having a bore with an internalcross-sectional area; an inlet to the tube, the inlet being positionedthrough the first end of the tube and the inlet having an inletcross-sectional area; an outlet from the tube the outlet having anoutlet cross-sectional area; a plurality of further inlets in the tubebetween an outside thereof and the bore; wherein the inletcross-sectional area is less than the outlet cross-sectional area.
 2. Afilter according to claim 1, wherein the inlet cross-sectional area isless than the internal bore cross-sectional area.
 3. A filter as claimedin any preceding claim, wherein the combination of the inlet and theplurality of further inlets provides a K-factor equivalent or greaterthan the K-factor of an open tube of the same dimensions as the tube ofthe filter.
 4. A filter as claimed in any preceding claim, wherein thefirst end is tapered such that the centre of the first end extendslongitudinally further than an outer portion of the first end.
 5. Afilter as claimed in any preceding claim, wherein the first end isdome-shaped.
 6. A filter as claimed in any preceding claim, comprising apipeline mounting means for mounting it to a pipeline.
 7. A filter asclaimed in any preceding claim, comprising a nozzle mounting means formounting a nozzle thereto.
 8. A filter as claimed in any precedingclaim, wherein the further inlets comprise slots.
 9. A filter as claimedin any preceding claim, wherein the further inlets extend generallyparallel to the longitudinal direction from the first to the second end.10. A filter as claimed in any preceding claim, wherein the furtherinlets extend for up to 75% or up to 50% of the length of the tube. 11.A filter as claimed in any preceding claim, wherein the further inletsextend for a portion of the tube between the first end and a middle ofthe tube.
 12. A filter as claimed in any preceding claim, wherein thereis at least 4 further inlets, optionally up to 20 or up to
 24. 13. Afilter as claimed in any preceding claim, wherein the further inletshave a width of at least 1 mm or optionally, a width of 1-3 mm or1.5-2.5 mm.
 14. A filter as claimed in any preceding claim, whereinspacing between the further inlets is 50%-150% larger than the width ofthe slots.
 15. A filter as claimed in any preceding claim, wherein thecross-sectional area of the inlet has a height to width ratio of at most2:1, optionally at most 1.5:1 or at most 1.1:1.
 16. A filter as claimedin any preceding claim, wherein the internal cross-sectional area of thetube has a height to width ratio of at most 2:1 optionally at most 1.5:1or at most 1.1:1.
 17. A nozzle apparatus, comprising a filter as claimedin any preceding claim, and a nozzle with a nozzle outlet, the nozzleoutlet having a nozzle outlet cross-sectional area.
 18. A nozzleapparatus as claimed in claim 17, wherein the inlet cross sectional areais less than the nozzle outlet cross-sectional area.
 19. A nozzleapparatus as claimed in claim 17 or claim 18, wherein the further inletsare of a suitable length where two in combination equals or exceeds theflow required to give the corresponding K-Factor of a nozzle attached tothe filter in use.
 20. A pipeline apparatus comprising a filter asclaimed in any one of claims 1 to 16, attached to a pipeline.
 21. Apipeline apparatus as claimed in claim 20, comprising a nozzle.
 22. Apipeline apparatus as claimed in claim 21, comprising a reducing bushconnecting the nozzle to the pipeline, wherein the length of the tubeextends beyond the reducing bush.
 23. A pipeline apparatus as claimed inany one of claims 20 to 22, wherein the filter is added to an end of thepipeline, and extends therein, substantially parallel to the mainlongitudinal axis of the pipeline.
 24. A pipeline apparatus as claimedin any one of claims 20 to 22, wherein the filter is added to thepipeline, and extends therein, substantially at a right angle to themain longitudinal axis of the pipeline.
 25. A pipeline apparatus asclaimed in claim 24, wherein the first end extends into the central 10%of the pipeline.
 26. A pipeline apparatus as claimed in claim 24,wherein the first end extends into the central 3-4% of the pipeline. 27.A nozzle apparatus, comprising: a filter comprising a tube extendingfrom a first end to a second end, the tube having a bore with aninternal cross-sectional area; an inlet to the tube, the inlet beingpositioned through the first end of the tube and the inlet having afirst inlet cross-sectional area; an outlet from the tube the outlethaving an outlet cross-sectional area; a plurality of further inlets inthe tube between an outside thereof and the bore; a nozzle with a nozzleoutlet, the nozzle outlet having a nozzle outlet cross-sectional area;wherein the inlet cross-sectional area of the filter is smaller than theoutlet cross-sectional area of the nozzle.
 28. Use of a filter asclaimed in any one of claims 1 to 16, with a nozzle.
 29. Use of a filteras claimed in any one of claims 1 to 16, with a sprinkler system forfirefighting/fire containment.
 30. Use of a filter as claimed in any oneof claims 1 to 16, with a burner head for hydrocarbons.
 31. Use of afilter as claimed in any one of claims 1 to 16, in a pipeline.